By his own admission, "no one knows" how the transition from Kim
Jong Il will play out, Bremmer says. The key issue now is whether
Kim Jong Il's designated successor, his youngest son Kim Jong Un,
will be able to consolidate power.

What is known is North Korea is an incredibly poor, incredibly
isolated nuclear power led by a totalitarian regime with a sudden
power vacuum at the top. "All of the things we've been most
concerned about ... suddenly those are real and they're much more
imminent," Bremmer says.

Those fears, what Bremmer calls "tail-end events," include
military attacks against South Korea, or the implosion of the
North Korean regime, leading to a refugee crisis on China's
southern border. In either scenario, there's a good chance both
U.S. and Chinese troops will be active on the Korean peninsula,
putting pressure on already strained relations between the two
superpowers.

An outright shooting war between the U.S. and China is "very
unlikely," Bremmer says, "but the potential for U.S.-Chinese
relations to deteriorate significantly in the [event] of a bad
North Korean outcome is very great."

And while Kim Jong Il's death does raise the possibility of a
better outcome — of a new regime seeking to reform North Korean
society or even reunification with the South — that hopeful
scenario is months away at best, he says.

"Anyone that's taking over, the first order of business - you
walk into a room and shoot the first person you see and then the
first person that moves," Bremmer predicts. "There are going to
be purges in North Korea because you need to establish that iron
fist before you can start opening it a little bit."